Absztrakt
Background/Aim: In an attempt to destroy pests and enhance food production, Nigerian local farmers are occupationally exposed to organophosphate pesticides (OP). During exposure, OP affect the nervous system by impairing the activity of acetylcholinesterase enzyme (AchE) thus leading to accumulation of acetylcholine at the neuromuscular junction. This defect in the cholinergic pathway has been consistently reported for over two decades in studies on the brains of those with advanced age. This study is aimed at determining the relationship between the levels of AchE activity with ageing in apparently healthy OP-exposed farmers as well as in unexposed controls in Nigeria due to paucity of data in this environment.
Method: This case-control study comprises a total of 104 apparently healthy participants. Fifty-two farmers (41 males, 11 females; aged 30-62 years) occupationally exposed to OP and 52 sex-matched unexposed controls (aged 38-60 years) were recruited from Idi-Ayunre farm settlements on the outskirts of Ibadan and University College Hospital, Ibadan respectively.
Results: Mean AchE level of OP-exposed farmers (7.22 ± 1.99 kIU/L) was significantly lower (p<0.05) than the controls (12.23 ± 1.67 kIU/L). Correlation of AchE activity with age was 0.189, p=0.179 and -0.325, p=0.019 for the farmers and controls respectively.
Conclusion: Low AchE activity level of the farmers indicates a persistent accumulation of acetylcholine at the neuromuscular junction, which may predispose them to intermediate
syndrome. Significant negative correlation between AchE activity and age of the controls probably indicates that the normal ageing process is associated with decreased AchE activity.
Keywords: Acetylcholinesterase, Organophosphate, Ageing, Farmers, Cholinergic Pathway
Résumé
Contexte / But: Dans le but de détruire les ravageurs et d’améliorer la production alimentaire, les fermiers locaux nigérians sont exposés professionnellement aux pesticides organophosphorés (PO). Au cours de l’exposition, PO affecte le système nerveux en altérant l’activité de l’enzyme acétylcholinestérase (AchE) conduisant ainsi à l’accumulation d’acétylcholine à la jonction neuromusculaire. Ce défaut dans la voie cholinergique a été régulièrement signalé depuis plus de deux décennies dans des études sur le cerveau des personnes ayant un âge avancé. Cette étude vise à déterminer la relation entre les niveaux d’activité de l’AchE avec le vieillissement chez des fermiers apparemment sains exposés au PO ainsi que chez des témoins non exposés au Nigeria en raison du manque de données dans cet environnement.
Méthode: Cette étude de cas-contrôle comprend un total de 104 participants apparemment en bonne santé. Cinquante-deux fermiers (41 hommes, 11 femmes, âgés de 30 à 62 ans) exposés professionnellement à l’OP et 52 témoins non exposés gendre-appariés (âgés de 38 à 60 ans) ont été recrutés respectivement dans les colonies fermières d’Idi-Ayunre à la périphérie d’Ibadan et au Collège Hospitalier Universitaire, Ibadan.
Résultats: Le niveau moyen d’AchE des fermiers exposés au PO (7,22 ± 1,99 kIU / L) était significativement plus bas (p <0,05) que celui des témoins (12,23 ± 1,67 kIU / L). La corrélation de l’activité d’AchE avec l’âge était de 0,189, p = 0,179 et -0,325, p = 0,019 pour les fermiers et les témoins respectivement.
Conclusion: Le faible niveau d’activité d’AchE chez les fermiers indique une accumulation persistante d’acétylcholine à la jonction neuromusculaire, ce qui peut les prédisposer au syndrome intermédiaire. Une corrélation négative significative entre l’activité de l’AchE et l’âge des témoins indique probablement que le processus de vieillissement normal est associé à une diminution de l’activité de l’AchE.
Mots-clés: Acétylcholinestérase, Organophosphoré, Vieillissement, Fermiers, Voie Cholinergique
Correspondence: Dr. O.M. Akinosun, Department of Chemical Pathology, College of Medicine, University of Ibadan, Nigeria. E-mail: bayoakin20022yahoo.com.
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